Oh, I misread and thought you were actually looking for "Test Channels". I think you were referring to Settings-Channels-Signal Strength which does not work (maybe when TAs are attached or only valid for OTA tuning)?

However, to see signal strength numbers tune 1 or more channels of interest and then visit Account & System Info-DVR Diagnostics where you will see info for each tuner including Signal Strength.

There is some weird bug here. I had this same thing happen on my Premiere. To get it to work I had to remove the CableCARD and tuning adapter, then do a channel scan, then reinstall then CC and TA. After that it started letting me into the signal strength meter.

if I go to settings/cable card/tuning adapter/DVR, then the main TiVo diagnostic screen shows both the SN and signal strength for both tuners, and from that I was able to discover that the rather long drop in one room was 20% weaker then it should be, hence, pixelation and blank channels.

I'm suspicious that the tuning adapter strips a fair amount of signal, enough to render the room unwatchable.

Cox will say it's my wiring.

I'll say the wiring was fine before the advent of Cox's TA and signal loss.

I should take a photo of the Cox drop box on my house - if you're looking for signal loss, the six splitters that are in there takes care of that no problem...lol.
Hopefully I can talk them into putting in a more elaborate combination signal booster/distribution amp of some kind, as switched digital seems to react very badly to signal loss (unlike good old fashioned cable tv did)

I should take a photo of the Cox drop box on my house - if you're looking for signal loss, the six splitters that are in there takes care of that no problem...lol.
Hopefully I can talk them into putting in a more elaborate combination signal booster/distribution amp of some kind, as switched digital seems to react very badly to signal loss (unlike good old fashioned cable tv did)

for that matter, if anyone is using a coax RF distribution amp with multiple outputs that is compatible with switched digital, please post the brand and model if you have it handy. That's likely the way this should end up going at some point. for example, anything from this list that would make Tivo's happy?

I should take a photo of the Cox drop box on my house - if you're looking for signal loss, the six splitters that are in there takes care of that no problem...lol.
Hopefully I can talk them into putting in a more elaborate combination signal booster/distribution amp of some kind, as switched digital seems to react very badly to signal loss (unlike good old fashioned cable tv did)

for that matter, if anyone is using a coax RF distribution amp with multiple outputs that is compatible with switched digital, please post the brand and model if you have it handy. That's likely the way this should end up going at some point. for example, anything from this list that would make Tivo's happy?

Yes something like that would be OK. I have an Electroline 8 way amplified splitter that I use at the drop that I bought about a decade ago. It has a return path so my cable modem coax also comes from the splitter. I also use 75 ohm terminators for the 3 outputs of the splitter not in use. Cox technicians that have visited a couple of times initially hate what I did there until they measure the signals coming out of the amp and admit everything looks good.

Yes something like that would be OK. I have an Electroline 8 way amplified splitter that I use at the drop that I bought about a decade ago. It has a return path so my cable modem coax also comes from the splitter. I also use 75 ohm terminators for the 3 outputs of the splitter not in use. Cox technicians that have visited a couple of times initially hate what I did there until they measure the signals coming out of the amp and admit everything looks good.

ah, mission Viejo...just up the road question: what is the purpose of the "return path" you mentioned. Also, the terminators do what exactly.
thanks

Your cable modem obviously needs upstream communication to work, so you need a return path through an amplifier. Some amplifiers only work in downstream direction which means you can't communicate back to headend. Cable modem and Tuning Adapters need to be able to communicate back so an amp/splitter with return path is essential.

The terminators just ensure that you don't introduce reflections and ghosting into the other splits. It's not essential but a nice/cheap finishing touch.

Your cable modem obviously needs upstream communication to work, so you need a return path through an amplifier. Some amplifiers only work in downstream direction which means you can't communicate back to headend. Cable modem and Tuning Adapters need to be able to communicate back so an amp/splitter with return path is essential.

The terminators just ensure that you don't introduce reflections and ghosting into the other splits. It's not essential but a nice/cheap finishing touch.